1. Technical Field
The present disclosure is directed to an axially oriented optical system and method of using the same, and more particularly, the present disclosure is directed to an apparatus for improving the computed radiography image generated by the axially oriented optical system and the method for using the same. The present disclosure is also directed to a method of using the optical system disclosed herein.
2. Background of Related Art
Previously, scanners of X-ray exposed phosphor plates performed their function on a flat-bed or the external surface of a rotating drum. These systems have problems that increase the cost and reduce the quality of the X-ray image. The undesirable results obtained with a flat-bed or rotating drum system are caused by the continuous changing of the angles and distances of the light beam paths used for stimulating the phosphor of the X-ray exposed phosphor plate. Also, the collection of the stimulated light is performed with a different path and angle for each position on the phosphor plate, thereby requiring complicated and expensive compensation measures. Additionally, the complications with attendant increases in cost are exacerbated when existing systems for supporting the phosphor plates do not maintain a fixed positioning during the scanning procedure.
Accordingly, many, if not all, of these deficiencies have been overcome in U.S. Pat. No. 6,291,831 to Koren, the entire disclosure of which is herein incorporated by reference. As seen in FIG. 1, the Koren Patent discloses a scanning apparatus 10 including a fixed, hollow cylindrical segment 12 having a central, longitudinal axis 16, the interior of which forms a concave surface for intimate contact with a medium for recording and/or readout 14 (e.g., a phosphor plate), a support structure forming a transport (not shown) for translational movement along the axis, a light source 18 (e.g. laser) mounted on the transport for movement therewith and for providing a beam capable of being directed along the axis, and a slanted mirror 26, angled 45° with respect to the axis and mounted on the transport for translational movement therewith and for rotational spinning around the axis.
According to the Koren Patent, the scanning operation involves the mounting of laser 18 and slanted mirror 26 in such a manner so that slanted mirror 26 bends a beam of light 90° and is capable of rotating the beam of light. Accordingly, the beam of light can then be manipulated to form a rotating spot on phosphor plate 14 which follows a path of a portion of a circle on phosphor plate 14. The transport 38, including optical system 10a having light source 18 and spinning mirror 26, and its subsequent movement to traverse phosphor plate 14 is coordinated with the rotative movement of the spot such that when the spot reaches the end of phosphor plate 14, transport 38 is moved the distance of one pixel in order for the next scan to be conducted. According to the Koren Patent, readout of a previously X-ray exposed phosphor plate is obtained a 635 nm laser 18 stimulating the crystal layer of phosphor plate 14 causing it to radiate light at 390 nm as the beam spot on the phosphor plate 14 makes its scan. The rotating mirror 26 receives the emitted light around its outer periphery for reflection onto a Schott type filter 24 which is transparent to 390 nm light and absorbent to 635 nm light. The light passing through filter 24 is applied to detector photomultiplier tube 20, which converts the light to an electrical signal that is amplified and gated to represent one pixel on the circular scan and converted to a digital number representing the brightness of the pixel.
In view of the aforementioned improvements and benefits of the Koren Patent over the prior art device, a need exists for an improved scanning apparatus which further reduces distortion, cost and the overall complexity of the operation while simultaneously improving the accuracy and quality of the resulting scan.